Problem: $ { {-5} \times \left[\begin{array}{rrr}{-1} & {3} & {1} \\ {-2} & {4} & {4}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{-5}\times{-1} & {-5}\times{3} & {-5}\times{1} \\ {-5}\times{-2} & {-5}\times{4} & {-5}\times{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{5} & {-15} & {-5} \\ {10} & {-20} & {-20}\end{array}\right]}$